Search

We aimed to evaluate the extractability of two reagents viz.0.15% CaCl2 & 0.01M Ca (H2PO4) for sulphur along with the sulphur availability index of mixed red and black soils. For this 86 soil samples were collected from mixed red and black soil regions and extracted with these solutions. Results showed that both these solutions extracted nearly similar amount of sulphur in black soils while the Ca phosphate solution extracted higher amount (13.9mgkg-1) compared to Ca chloride solution (11.5mgkg-1) in red soil regions. Considering all the 86 soil samples tested, there was an excellent correlation between the extractable sulphur, the highest correlation being reported from black soils (R²= 0.97). Sulphur availability index was found to be higher in black soils (mean 6.6) compared to red soils (mean 5.1). Also the content of adsorbed sulphur was found to be high in red soils (2.4mgkg-1) compared to black soils (1.5mgkg-1). Correlation matrix and regression equations (Ca phosphate S= 5.00+ 0.77 Ca chloride S) were worked out between the extractable sulphur and soil properties to justify the results. [ABSTRACT FROM AUTHOR]

In the present investigation, various forms of sulphur (S) viz., total S, organic S, inorganic S and available S were estimated in soils under four different land uses viz., Rice-rice, rice-green gram, mango orchard and a fallow. Soils samples were taken up to a profile depth of 0.60m at 3 depths i.e. 0-0.20m, 0.20-0.40m and 0.40-0.60m. The soils were found to be slightly acidic to moderately acidic in reaction (5.83-6.59), showing an increase along the depth irrespective of the land use pattern. Soil organic carbon (SOC) content (mean 5.5 gkg-1) was found well above the low level of SOC in soils. Calcium carbonate content, bulk density and clay content of soils didn't maintain any definite pattern along the depth. All forms of S were found to decrease along depth irrespective of the land use patterns. The available S content ranged from 12.2 to 21.4mgkg-1 of soils. The relative preponderance of all the forms of S followed the order: mango orchard> fallow> rice-rice> rice-green gram. On an average organic S and available S fractions constituted 93 and 6 per cent of total S respectively. A correlation matrix revealed that all the forms of S maintained a significant positive correlation with SOC content while a negative correlation with pH of the soils. The results of the study will be useful in managing the different fractions of S in soils in order to maintain its availability well above the critical level. [ABSTRACT FROM AUTHOR]

To better cope with unfavorable climatic conditions and perform optimal physiological functions, the silkworm Bombyx mori secretes some of its defensive enzymes in the hemolymph. To understand the extent of enzyme secretion in the hemolymph, we studied the profiles of defense enzymes in different silkworm breeds. We collected and analyzed the hemolymph of 5th instar larvae of 21 different bivoltine silkworm breeds with different characteristics for protein content and activities of enzymes such as catalase, peroxidase, polyphenol oxidase, amylase, and protease. The results revealed significant differences between the breeds in terms of protein and defensive enzyme activities. The activity of catalase, peroxidase, polyphenol oxidase, amylase, and protease varied between silkworm breeds, with an average activity of 8.791 U mg−1, 0.203 U mg−1, 0.42 U mg−1, 0.264 mg ml−1 min−1 mg−1 and 0.193 µg ml−1 min−1, respectively. To understand the genetic relationship between the silkworm breeds in terms of the activity of defensive enzymes, we constructed a dendrogram using Euclidean distance. The 21 silkworm breeds were grouped into five different clusters with different enzyme activities, revealing sufficient diversity between the silkworm breeds that can be used for parental selection in silkworm breeding programs. This study is highly informative in enhancing knowledge on the role of defensive enzymes in the development of new silkworm breeds that can adapt to adverse environmental conditions. [ABSTRACT FROM AUTHOR]

Zinc biofortification in rice can be improved by altering Zn application timing and placement and cultivar choice. We made a comprehensive assessment on this, analysing Zn, Fe and phytic acid in whole grains and processed brown, white and cooked rice obtained from six cultivars raised with Zn applied through soil and/or foliar supply at different phenological stages of the crop and measuring Zn bioavailability in cooked rice. Pathways for Zn enrichment (27.4–92.6% over control) by Zn fertilization with different application protocols and cultivars were elucidated. Such enrichment of Zn was associated with depletion in Fe (6.5–29.4%) and phytic acid (14.8–30.4%). However, the loss of Zn on processing of rice grains increased on Zn fertilization (12.6–28.7 mg kg −1 ) because of a preferential allocation of applied Zn into bran and aleurone of the grains. Despite such loss, application of Zn caused a net increase in Zn bioavailability (52.2% over control) in the cooked product. Using the ranksum scoring technique, we found cultivar GB 1 and Zn supply through soil (basal) + 2 foliar applications achieved the most effective biofortfication of Zn in rice by optimizing grain yield, and enriching Zn and its bioavailability in cooked grain with least antagonism of Fe availability. [ABSTRACT FROM AUTHOR]

Soil enzymes play vital role in nutrient mineralization and their activity in soil is an excellent sensor in predicting the nutrient supplying capacity to plants. A field experiment was conducted to study the effect of long-term fertilization and maize hybrid on seasonal and temporal changes in soil enzyme activities (phosphatase and dehydrogenase). There were ten treatments each replicated four times viz., T1- 50 % NPK, T2 - 100% NPK, T3 - 150% NPK, T4 - 100% NPK + hand weeding, T5 - 100% NPK + ZnSO4, T6 - 100% NP, T7 - 100% N alone, T8 - 100% NPK + FYM, T9 - 100% NPK (-S) and T10 - Control. The results showed that during monsoon fallow period, dehydrogenase activity increased, while phosphatase activity recorded lower values after monsoon rainfall. Unlike phosphatase activity, dehydrogenase activity followed a declining trend as growth stages of hybrid maize (Co-6) proceeds. Among the treatments, 100 % NPK + FYM @ 10 t ha-1 (T8) recorded the highest activities of these enzymes emphasising the importance of integrated nutrient management in improving biochemical properties of soil, thereby sustaining the soil health over long run. [ABSTRACT FROM AUTHOR]

Study of soil organic carbon pools is helpful to understand the mechanism of carbon sequestration in soil. It was hypothesized that different management practices and sources of organics applied to soil will change the carbon allocation into various pools. The changes in total organic carbon (TOC) and its pools of different oxidizabilities (very labile, labile, less labile and non-labile pools) were investigated along with other fractions – microbial biomass carbon, particulate organic carbon, active carbon and oxidizable organic carbon – in soils under a 24-year-old double rice (Oryza sativa L.) cropping system with different management strategies in a hot, sub-humid region of India. Cultivation over the years caused a net buildup of TOC under different treatments. About 27.3, 48.2 and 54.1% of the C applied through green manure (GM), farmyard manure (FYM) and GM + FYM, respectively, was stabilized in the soils. Application of GM and FYM increased C in very labile and less labile pools, respectively. Of the analyzed pools, permanganate oxidizable and microbial biomass C were more sensitive to management practices and hence are considered important indicators of soil quality, and balanced fertilization with GM + FYM is considered suitable management for sustaining soil health under the double rice system. [ABSTRACT FROM AUTHOR]

Using 12 long-term (of 15 to 42 years duration) experiments with different cropping systems under various soils and agro-climatic conditions, we studied how different (inorganic and integrated) nutrient management practices influenced boron (B) availability in soils, and its nutrition of nine crops. To this end, four nutrient management practices viz., NPK (recommended dose of N, P and K), NPK + FYM (farmyard manure), control and fallow, which were common in all the experiments, were selected and their effects on B availability in soils were tested using four commonly used methods viz., hot-CaCl 2 (HCC), KH 2 PO 4 (PDP), mannitol-CaCl 2 (MCC) and hydrochloric acid (HCl) in relation to B nutrition of wheat, rice, cowpea, sorghum, sesame, mustard, groundnut, soybean and lentil. Amounts of B extracted by the four different methods followed the order HCC = HCl > MCC > PDP across the tested soils. Averaged over the extractants, long-term nutrient management practices with NPK + FYM resulted in 15% increases in available B in soil over the control, which produced 20% increase in plant tissue B concentration. Such increases with integrated (NPK + FYM) nutrient management practices maintained available B in soils and plant tissues above its critical limits that supplied adequate amounts of B for nutrition of all the tested crops grown intensively for so many years. A B balance study in six experimental sites showed a net B accumulation over time as irrigation water contained and supplied (130–296 g B ha−1 year−1) more B than removed by harvested crops. Of the four methods used, HCC was the best for assessment of availability of B in soils under long-term cultivation. • 15–42 years integrated NPK supply maintained adequate B in soils and in plants. • Long-term nutrient management caused a positive balance of B in soils. • Hot-CaCl 2 was the best extractant in capturing changes in B availability in soils under LTFE. • B-rich irrigation water and to a lesser extent FYM caused B accumulation in soils. [ABSTRACT FROM AUTHOR]

Highlights • Organic carbon stock in soil increased by 22% under long-term intensive cropping with NPK + FYM in Vertisol • Stock of inorganic carbon decreased (13.2%) in soil on carbon addition through FYM • Macroaggregate associated C was higher than microaggregates • About 0.96 Mg C ha−1yr−1need to be incorporated into soil to maintain SOC level • Significant correlations exist between SOC pools and yield of sorghum-wheat system Abstract We investigated dynamics of soil organic carbon (SOC) i.e. total soil organic carbon (TOC), oxidisable organic carbon (OC) and its different pools viz. very labile (C VL ), labile (C L ), less labile (C LL ) and non-labile (C NL ), and various sized aggregate associated carbon (AAC) and also its sequestration along depth (0-0.15, 0.15-0.30, and 0.30 -0.45 m) in a typical Vertisols under hot semi-arid agro-climatic conditions. Such dynamics were studied under different soil management practices viz., control, NPK (100% recommended doses of N, P and K fertilizers, RDF), NPK + FYM (50% N and whole of the RDF and 50% N through FYM) and fallow using a 28 year old long-term experiment with sorghum ( Sorghum bicolour L.) – wheat ( Triticum aestivum L.) cropping system. On average, a higher proportion (70% of TOC) of SOC was found in passive pool (less labile + non labile) than active one (very labile + labile) throughout the profile. The proportion of active pool was, however, higher under balanced (NPK) and integrated nutrient management practices (NPK + FYM) over the others followed. Long-term intensive cropping with NPK (15.1%) and NPK + FYM (22%) caused a net enrichment in SOC stock over the control. To offset the loss of C and maintain the SOC level, a critical amount of 0.96 Mg C ha−1yr−1 was needed to be incorporated into the soil. Out of the total water stable aggregates (WSA), mesoaggregates (0.25–2.0 mm) predominated (73.6%) followed by micro (16.4%), and macroaggregates (10.7%) at surface soil. Amount of carbon associated with different sized aggregates had the following trend: mesoaggregate (52.3%) > coarse microaggregate (13.7%)> coarse macroaggregate (13.5%)> (silt + clay) sized aggregate (13.1%)> fine microaggregate (12.2%). Balanced fertilization with organics thus provided not only higher yield but also increased C sequestration in Vertisols even with intensive cropping of sorghum-wheat system under hot semi-arid conditions. [ABSTRACT FROM AUTHOR]

Information on optimization of nutrient management (NM) protocols for maize-mustard cropping system to achieve sustainability with regards to crop yield, nutrient use efficiency, soil quality, energy balance and profitability is limited. We evaluated NM practices for maize-mustard cropping system in a comprehensive manner using five criteria such as i) crop yield response, ii) recovery efficiency of plant nutrients, iii) soil quality index, iv) energy efficiency, and v) profitability of cultivation for acidic soils under subtropical conditions of northeast India. Eight NM treatments comprising of organic [farmyard manure (FYM)], inorganic fertilizers including micronutrients (Zn, B) and some of their combinations were tested using randomized complete block design with three replications for five consecutive maize-mustard cropping sequences during 2010–2015. Yield and yield related characters of the crops were recorded and nutrient concentration in representative plant parts was analysed for determination of their uptake, harvest index and use efficiency at each harvest. The initial and post-harvest (after fifth cropping sequence) soil samples were collected at 0-0.20 m depth from each of the experimental plots and analysed for physical, chemical and biological soil quality attributes. Energy and economic efficiency of the cropping systems was computed using fertilizers, seeds, plant protection chemicals, farm machineries for tillage and irrigation and human labor inputs and crop yield outputs. Yield and yield related characters, plant nutrient uptake and use efficiency, energy and economic variables of cultivation and soil properties were subjected to analysis of variance. Balanced supply of nutrients including micronutrients (Zn, B) through integration of organic and inorganic sources was proved to be sustainable in respect of crop productivity, economic viability and maintenance of environmental health. This helped improve recovery efficiency of applied nutrients as well as soil quality by increasing soil organic C, microbial biomass C and plant available nutrient content. Integrated use of 120-35-50-5-1 kg N-P-K-Zn-B with 10 Mg FYM ha −1 was proved to be the best due to significantly higher crop yield (5.80 Mg kernel and 1.22 Mg grain ha −1 for maize and mustard, respectively), recovery efficiency of applied nutrients (average recovery efficiency 64.5%), soil quality index (2.0), energy efficiency (energy gain 234,530 MJ ha −1 ) and economic return (marginal rate of return 3.5) as compared to the other NM treatments. Application of 120-35-50-5-1 kg N-P-K-Zn-B ha −1 or its combination with reduced rate of organic manure (5 Mg FYM ha −1 ) can also achieve sustainability with minimum conciliation with yield, nutrient recovery, environmental quality and economic benefit. Supply of nutrients only through organic sources (e.g., FYM) will not be sustainable for maize-mustard cropping system. [ABSTRACT FROM AUTHOR]

Zinc application may produce grains with increased Zn, but it cannot ensure a higher bioavailable Zn in the ultimate food products prepared from the grain. The aim of the present study was to optimize Zn fertilization protocols for different wheat cultivars with a view to achieve a higher enrichment of Zn in grains, and reduced Zn-Fe antagonism and loss of Zn on processing to achieve enhanced bioavailability of Zn in flour. We evaluated the effectiveness of Zn biofortification in wheat using four criteria viz., i) magnitude of Zn sequestration in flat breads of wheat, ii) Fe retention in it, iii) maintenance of a favourable phytic acid: Zn molar ratio in breads and iv)enhanced grain yield. Zinc fertilization protocols involving its application through soil, foliar spraying or both at critical phenological stages were tested with six cultivars. Both the grains and flat breads were analysed for Zn, Fe and phytic acid. Zinc fertilization yielded Zn dense but Fe- and phytic acid-depleted grains. However, 40–75% of Zn enrichment in grains was lost during processing to prepare the breads. Zinc application through soil + foliar at maximum tillering and flowering stages with cultivar UP 262 excelled in effecting not only higher grain yield but also grain Zn biofortification that ensured a net gain in Zn in breads, and its Zn bioavailability through a reduced antagonism with Fe and phytate. [ABSTRACT FROM AUTHOR]

A pot experiment was conducted to study the influence of liming on changes in different forms of acidity in relation to soil properties. Thirty-six surface (0–15 cm deep) soil samples were collected from different soil orders, namely Entisols, Inceptisols, Alfisols, and Entisols of coastal saline zone of West Bengal, India, and incubated for 21 days with three doses of lime [i.e., no lime (L0), half lime (L1/2), and full lime (L1)]. Results of analysis of soil showed that there were significant increases in pH in water (pHw) and pH in 0.02 M calcium chloride (CaCl2) (pHCa) (1.3 and 1.5 units) and decrease in total acidity, hydrolytic acidity, exchange acidity, electrostatically bound aluminium (EBAl3+), and electrostatically bound hydrogen (EBH+) upon liming being from 1.53 to 0.57, 1.40 to 0.54, 0.13 to 0.03, 0.08 to 0.01, and 0.06 to 0.02 cmol (p+) kg−1, respectively. The decrease in values of all the forms of acidity was greater in L1than in L1/2treatment under Entisols of the terai zone, followed by Entisols of coastal saline zone, Inceptisols, and Alfisols. The forms of acidity showed significant positive correlation with each other but negative correlation with pHwand pHCa, except for EBH+. [ABSTRACT FROM AUTHOR]